What is the ruling on a man shaking hands with a non-mahram woman, whether young or old, if he intends nothing more than a handshake and considers her like his sister?

Shaking hands with non-mahram women is not permissible, and the claim of necessity here is unfounded. If the woman is young or old enough to be desired, the matter is clear. If she is an old woman who is not desired, some scholars have permitted shaking her hand, but it is safer to avoid all of that due to the generality of the evidence. It is also not permissible to work in places where men and women mix in a prohibited manner.